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From "Ning Zhang (JIRA)" <j...@apache.org>
Subject [jira] Created: (HIVE-949) Object deepCopy in GroupBy Operator
Date Mon, 23 Nov 2009 20:41:40 GMT
Object deepCopy in GroupBy Operator
-----------------------------------

                 Key: HIVE-949
                 URL: https://issues.apache.org/jira/browse/HIVE-949
             Project: Hadoop Hive
          Issue Type: Improvement
            Reporter: Ning Zhang


In GroupByOperator, objects are first deep copied and then check whether or not the object
is in the hash table (in hash-mode aggregation). In fact, object deep copy could be very expensive
(around 5% CPU time). A simple change could be generate the object without deep copy through
ObjectInspector and check its existence in the hash table. If not exists, we call deep copy.


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